1. Field of the Invention
The present invention relates to an optical disk storage and handling system and, more particularly, to an optical disk cartridge, an optical disk drive and driving method using the optical disk cartridge, and an optical disk changer and method for handling a plurality of optical disk cartridges.
2. Description of the Related Art
Optical disks have been popular in recent years as a data storage medium for recording and reproducing music and audio-video works. Due to the random accessibility of optical disks, the optical disks have become popular for storing computer readable information. Recent developments resulting in increasing storage density of the optical disks have given rises to requirements that disk cartridges protect optical disks therein from dust and dirt which may cause errors.
In order to handle a large amount of information such as image data, an optical disk storage and handling system requires a very large storage capacity and must be capable of handling a large number of optical disks. Furthermore, as audio-video equipment and personal computers have been miniaturized and become portable, it has become necessary to reduce the size of the optical disk storage and handling system having a large storage capacity.
Conventional optical disk cartridges are standardized, for example, as described in ISO/IEC-10090 (Information technology--90 mm optical disk cartridges, read only and rewritable, for data interchange). Known disk drives used for handling conventional disk cartridges are described in U.S. Pat. Nos. 5,056,073 and 5,062,093.
In general, a conventional disk cartridge includes a case consisting of an upper half and a lower half and a slidable shutter. An optical disk is housed within a case in a space between the upper and lower halves. The case has an opening for inserting an optical pickup and the slidable shutter is provided to cover the opening when the disk cartridge is not in use. The shutter protects the optical disk from dust and dirt by preventing dust from getting into the case and by protecting the optical disk surface from fingerprints of an operator, for example.
The disk cartridge has a write-protect mechanism including a hole of the disk cartridge and a sliding lever provided in the hole. The hole can be opened or closed depending on a position of the lever. Whether the disk cartridge is write-protected or not is determined by detecting whether the hole is opened or closed using a write-protect detecting mechanism.
Next, a disk loading mechanism of a conventional disk drive using such disk cartridges will be described. A disk cartridge is inserted into a cartridge holder through a slotted opening provided in the front face of the disk drive. During insertion, the disk cartridge shutter is slid open by a link mechanism incorporated in the cartridge holder, so that a read/write portion of the optical disk is exposed through the opening.
The disk cartridge moves inward together with the cartridge holder while being further inserted into the disk drive. The cartridge holder moves inward by a horizontal distance S and downward by a vertical distance D to a read/write position via a guiding mechanism including a guide roller, a guide groove and the like.
The disk cartridge moves downward with the cartridge holder and is ultimately fixed at a correct position for read/write operation by a positioning pin. The optical disk within the disk cartridge is placed on a turntable provided on a spindle motor and is chucked. Thus, loading of the optical disk is completed so as to keep the optical disk in an appropriate position for read/write operation with respect to the optical pickup.
When the disk cartridge is to be pulled out from the disk drive, the cartridge holder is moved upward by a loading motor which pulls a slider against a slider spring, whereby the optical disk is taken from the turntable. By reversing the loading procedures, the disk cartridge is returned to a position to be pulled out by an operator.
Nevertheless, the conventional disk cartridge and the loading mechanism of the conventional disk drive have the following problems:
The movement of the disk cartridge downward to the spindle motor after insertion in the horizontal direction results in an aperture in an upper portion of the slotted opening of the disk drive. Dust easily enters the disk drive through the aperture. The conventional loading mechanism opens the shutter automatically when the disk cartridge is inserted in the disk drive. Accordingly, when the disk cartridge remains in the disk drive, the optical disk is exposed to dust which may cause errors.
Furthermore, a conventional disk changer apparatus includes a disk stacker which houses a plurality of disk cartridges and a disk handling mechanism. The disk handling mechanism is, typically, formed in an arm-shape and picks up one of the disk cartridges from the disk stacker and then inserts it into a disk drive device which is fixed at a predetermined position in the disk changer apparatus. The size of the disk changer apparatus has to be large due to the disk handling mechanism which moves a selected disk cartridge from the disk stacker to the disk driving device. In addition, since the arm-shape handling mechanism is provided on a disk inserting side of the stacker, the handling mechanism is an obstacle to insertion of the disk cartridges into the stacker. In addition, it is difficult to change disk cartridges rapidly because each disk cartridge has to be transferred a relatively long distance between the disk stacker and the disk drive device to access the optical disk.